The non-classical distribution function formalism is used for studying the electron transport in a nanosystem. We calculated the current-voltage characteristics of a triple barrier one-dimensional nanostructure which is connected to three-dimensional (highly doped semiconductor) reservoirs by the ohmic contacts. We also estimated the peak-to-valley ratio for the considered nanostructure and discussed the effect of switching the bias from peak-to-valley and from valley-to-peak voltages.